This invention relates to cabinet construction and, in particular, to a refrigerator appliance cabinet construction.
Insulated wall structures are known wherein the cabinet wall structure includes an inner panel or liner, an outer shell, and a body of foamed-in-place insulation therebetween. A sheet of fibrous material has been employed to extend across the space defined by the front edges of the liner and shell to define a boundary of the foamed-in-place insulation. The fibrous material also allows air to be vented during the foaming process.
In some instances, the technique of foaming-in-place utilizes a sealing material, such as a flexible polyurethane foam pad, which is captured between the liner and shell but is movable enough to allow air to be vented during the foaming process. This type of technique is shown in U.S. Pat. No. 3,489,477, assigned to the same assignee as that of the present invention.
In U.S. Pat. No. 3,989,328, a strip of rigid foam is provided for closing the front opening between the inner liner and outer shell of the appliance cabinet. The rigidity of the foam strip permits the strip to serve as a means for holding the liner centered within the cabinet shell during the assembly thereof. The foam strip also has vent passages which permit air and gases evolved in the foaming operation to escape from the insulation space between the liner and cabinet shell. The passages self-seal, as by being plugged with the foam.
A problem encountered in making refrigerators involves preventing the foam from contacting and plugging up openings in the front of the outer shell that should remain open. Such openings, for example, are for switches utilized in turning on an interior light of the refrigerator when the doors are open and off when closed. It is desirable to be able to prevent the foam, during assembly of the liner and outer shell, from plugging up these openings so that the switches and electrical wires may be subsequently assembled without being hindered by any solidified foam in that area. To prevent the foam from reaching these openings, foam stop means may be employed which, desirably, have venting means so that air and gases evolved during the foaming operation may be expelled from between the liner and outer shell, thus allowing the foam to completely fill the insulation space therebetween. U.S. Pat. No. 3,989,328 does show such a venting means; however, it has been found in practice that the volume of air and evolved gases that must be expelled from the insulation space is considerable and the vent means must be relatively large to accommodate the process. However, it has also been found that when the vent passages are large enough to adequately handle the volume of air and gases being expelled, they are prone to also allow the foam to pass therethrough into the area that is to be kept free of the foam. This is particularly the case in connection with side-by-side refrigerator/freezers, that is, those refrigerating appliances that have side-by-side doors with the freezer on one side of the cabinet and the fresh food on the other. In this kind of refrigerator cabinet in particular, a large volume of air and gases must be expelled from the insulating space between the liner and outer shell during the foaming-in process and it is expelled out the bottom of the cabinet where the openings for switches, etc. are located.
By this invention, there is provided a foam stop means to prevent the foam from reaching openings at the front of the refrigerator cabinet, yet have sufficient venting means to allow the passage of gases and air being expelled from the insulation space between the liner and outer shell during the foaming-in process. In addition, this foam stop means is made of rigid insulating material that adds strength to the assembly, is easy to install during cabinet assembly and has good thermal insulation characteristics.